Learjet 35-A

Nothing else can take you there faster, on less fuel. Absolutely nothing.

It's a incontrovertible fact. The Learjet 35A covers more miles in less time on less fuel than any other business jet.

Period.

In fact, even slower jets consume more fuel than the Learjet 35A. The Cessna Citation S/II, for example, takes about 15 minutes longer than the Learjet to complete a typical 500-n.m. mission at high-speed cruise--and gulps down 100 ponds more fuel in the process.

No other aircraft offers a better blend of speed, efficiency, and versatility than the Learjet 35A.

Ask the U.S. Airforce. Before selecting a manufacturer for their C-21 utility jet, they conducted a four-month comparison of contenders. When it was over, the choice was clear. The USAF ordered 80 Learjets.

It has the mild character of an airliner, combined with the umph of a fighter jet. So it's perfect as a trainer for both types of aircraft.

There are not a gazillion buttons to press, perfect for lazy pilots that want mileage.

It is a beast to fly. It is possible to take off from a postagestamp, pull up like a rocket and land on a dime.

This aircraft needs more pilots! (and positive reviews)

Negative

The interior is not of a Learjet, the instruments were designed for the Cessna Citation Bravo. The looks and animations of the aircraft is not sleek and finished.

Oddities

For this aircraft but perhaps also for other aircraft with this setup. Some oddities are probably on-purpose.

The ADF frequency in the cockpit is not in sync with the Radio window.

NDB beacons can be entered as NAV1 or NAV2. That's a big positive! They will give distance but no radial for the autopilot.

If changing course (radial) in the Radio Window be sure to press apply to feed the Primus. For the other values the apply key isn't needed.

If FMS is used once, the Primus will get confused and ILS beacons will not show the glidescope.

In the Autopilot Pitch (VNAV) and V/S do not work as expected.

If the Autopilot is turned on it will also turn on a vertical control, Pitch, V/S or Altitude depending on what is pre-selected. Standard is Pitch.

I have not discovered any effect from the Roll Knob.

NAV2 can only be used for reference. It can not be used for radial navigation.

The compass is b0rken. It has a strange deviation and can not be set with Instrument settings. The compass shows Magnetic, the NAV (also when an NDB has been entered) indicators True, the ADF indicator Magnetic, the course deviation bars show Magnetic, extremely confusing. Since the course bars show Magnetic, VOR navigation (Autopilot) is also done with Magnetic. If this is true for this aircraft it probably is true for all Primus 1000 aircraft.

In FlightGear the limits are more flexible as the real thing. If you would cross over limitations in reality the thing would go poof.

The data gathered is not guaranteed to be 100% accurate, some sources contradict each other. The most probable reason is that many aircraft have been refitted and improved (wing-tips, undercarriage, fuel tip) and often models are mixed (C21, 36, 35A etc).

Aircraft configuration

Please note. Despite best efforts the description does not depict the real aircraft. If you have one of the real things, call me, I'd love to hop aboard, but use the Flight Manual for your planning.

Fuel system

This Learjet is equipped with five fuel tanks. The two characteristic tip tanks, two wing tanks and one tank in the fuselage. The tanks are filled from the tip tanks and during filling the fuel is distributed by gravity. This means that after filling each tank has the same percentage of fuel.

All weight above 13,500 lbs should be wing and tip tank fuel.

The flight characteristics are negatively influenced by the tip tanks (Dutch roll and front weight) that is why it is common to burn the tip tanks first.

From Equipment=>Fuel and Payload it is possible to open or close a tank.

There is only one type of jet fuel in FlightGear. To go from Gallons to pounds, multiply with 6.72 .

Calculate from your planning the amount of fuel needed.

1st hour 223 Gallon

2nd hour 194 Gallon

3rd hour 164 Gallon

4th hour 134 Gallon

For flights less then two hours fill the tanks to the max. landing weight (15,300lb) then add the amount of expected fuel burn. (i.e. for a two hour flight fill to 15,300 lb, then add 223+194 Gallons)

Make sure there is a reserve of at least 90 Gallons in each wing that can be used for a go-around procedure.

Load the amount of fuel using Equipment=>Fuel and payload. Made sure the sliders are above each other so to simulate gravity.

Before taking off close the wing and fuselage tanks keeping only the tip tanks open.

After approx an hour into the flight open the fuselage tank.

After another half hour open the two wing tanks.

Just before approach check the content of the tip tanks. If a tank holds more as 138 Gallons jettison (empty) the tip tanks. Else they could snap off during landing.

There is an upgrade kit available to increase the length of the tip tanks giving a longer range of the aircraft.

Altitude and flight planning

Flight duration 1 hour, fly between FL300 and FL330.

Flight duration 2 hours, fly between FL330 and FL370.

Flight duration 3 hours, fly between FL370 and FL400.

Flight duration 4 hours, fly between FL400 and FL430.

Engines

The engines can take N1 105% for about 5 seconds before you will have to replace them. They can take N1 103% for about 5 minutes which is just sufficient for an emergency ascend to FL180. (some documents state 1 second for 105% and 1 minute for 100...103%) Continues power is possible at N1 101.5% but it's best is to keep at or below 100%. Optimal cruise and climb, lowest fuel burn, is at N1 85%.

Flaps and brakes

The flaps have three settings.

8o makes the wings more efficient and provides a good deal of additional lift. It does not slow down the aircraft much. To make the aircraft take off easier, reducing the need for new tires, this setting is used. If you are sure to stay below 200 knots during VFR flight, touring over the country side, the throttle has more grain giving perfect control during slow, low level flight. The Learjet 35-A is certified for VFR flight.

20o gives enough drag to slow down an aircraft. It also makes the wings more efficient during take off and this setting should be used with heavy loaded aircraft.

40o is almost like a handbrake on your car. The aircraft wants to make a full stop on this setting. It provides some additional lift and should be used during take-off with with MTOW but be sure to shift to a lower setting as soon as possible. With this setting you can perform an emergency descent with a negative pitch of up to 40. During landing you will have to set N1 between 60...80% to prevent stalling. With higher speeds the aircraft will have an extreme pitch behaviour.

The three settings are sufficient for normal use however there is an upgrade kit available giving a notch at 15 and 30. This makes the aircraft more flexible as a cargo transporter.

Spoilerons (airbrakes) can be used at any speed below VMO. One thing to remember is, do not combine spoilerons with flaps, except during slowing down on the runway. The flaps want to push down the nose, the spoilerons do not have this effect. Be sure to retract them when you have reached the desired speed.

Reversers can only be used below decision height and on the ground. If enabled the amount of reverse thrust depends on the throttle. It is advised to keep N1 below 85%. It should not be used below 60 knots with to prevent debris flying around everywhere, even entering the engines. Reversers can be used, on ground, to "powerback" (go backwards), use low thrust and never (ever!) use the brakes, use forward thrust instead. After use of the reversers they must receive an inspection therefore they can only be used once. It is against regulations to use reversers prior to take-off and with touch-and-go landings. It is a known risk that reversers can get stuck in the reverse position. (14 CFR Part 39 Amendment 39-4361; AD 79-08-01 R1 & MIA97FA213) Reversers will reduce the length needed for landing however plan to use a runway with sufficient length without reversers.

Cockpit and control panel

This Learjet 35-A has been refitted with the control panel of the Cessna Citation Bravo. The usage and information provided is the same.

Please note that most heading information the Primus 1000 gives is Magnetic except the arrows, those show True. As the deviation-bars also show Magnetic radio navigation should be based on Magnetic. Since runway headings are based on True they should be corrected for the magnetic deviation before entering this information in the machine. For an ILS there isn't much of a problem since it gives just one radial, but for airfields without an ILS but with a VOR-DME the deviation can be well noticeable. The deviation can be retrieved from Equipment => Instrument Settings => HI offset. Add this value to the heading of the runway.

Autopilot

Differences from expected behaviour,

VNAV/Pitch will set climb, level or descend depending on the previous setting on the Altitude. If you were climbing with autopilot, Pitch will continue the climb.

VNAV/Pitch will not be lit on the dashboard.

VS does not work.

B/C Back Course does not work.

V/S Pitch up down does not work.

Roll Knob does not function.

Passengers and cargo

This aircraft is configured for 8 passengers, 6 luxury leather seats, one flight attendant and one flap-down seat. There is room in the front for the luggage of the pilot and co-pilot with a max of 100 lb. Between the wings, just behind the last seats is the cargo hold that has room for 500 lb.

The maximum weight of the aircraft, without fuel, is 13,500 lbs.

It is possible to overload the aircraft with the risk of leaving the undercarriage and tires somewhere on the tarmac. There is an upgrade kit available making it stronger.

If your passengers are claustrophobic advise them to wait for an airliner. The width of the tube is 4.95ft (1,8 meters) and the height is 4.4 ft (1,34 meters) so not much room to take a walk.

The more weight in the back the better, so have your passengers sit from the back to the front.

Warning systems

This aircraft has a MK VIII installed. It will callout the height and will give out warnings about flaps, landing gear and when the ground is too close. Most annoying is the alarm sound for lowering the gear.

TCAS is installed and visible on the MFD. Use the centre console to change visible radar range.

The FC 530 AP will warn for stall and overspeed.

The stall warning will give a high pitch sound. In this simulation there is no stick shaker. The stall warning will shutdown the autopilot and will enable the caution alarm. The stall warning system is not perfectly capable of detecting a stall while banking. Contrary to the real aircraft this simulation does not include a stick push. When the alarm sound the aircraft is in a stall, not nearing a stall.

The overspeed alarm sounds like a clicking sound, a reason to slow down quick before the aircraft disintegrates. It will enable the caution alarm. Limitations are:

Caution when Mach > 0.74 and no AP

Caution when KIAS>300 and ALT < 8,000

Caution when KIAS>350 and ALT > 8,000

Stick pull KIAS>354 or MACH >0.82

The Caution alarm sounds like honk honk, silent, silent. It can be stopped after the cause of the alarm has been taken away. Just press the button to shut it off. Check the aircraft limits when the cause of the alarm is unknown.

The autopilot will also shutdown in the following events: G-forces over the limit or engines have stopped.

Stall behaviour

When the speed is reduced the Lear will nose-dive before there is a stall. If you fight that behaviour, pull up, you will find that a stall without flaps can cause loss of control diving left or right to start a spin. With flaps you can steer left and right without loosing control sinking at an extreme rate. To get out of a stall the easiest steps are to give max power and lower nose. With one engine down however max power will worsen the situation so lower nose to pick up speed, get control back and then increase thrust slowly. Stall character of the Learjet 35-A is described as very mild.

Flight characteristics

The Learjet loves to go up, it loves to go down. But it doesn't like level flight. The Autopilot has a Yaw Damper function to help level flight. Heavy tip tanks combined with low speeds can cause a Dutch Roll, it will make your passengers sick and can,in extremes, cause loss of control.

This machine is build to be happy above FL390, it's possible to fly KTAS 471 keeping N1 at 100%. Below FL390 the engines are not strong enough. The ceiling at 45,000 is for the standard machine, for research aircraft have been fitted with better seals keeping the cabin pressurized at higher altitudes.

Above 220 KIAS and/or above FL180 the aircraft should be flown with Autopilot since the slightest stick movements, above that speed, can cause scary things.

There are some things you should not do,

Give full throttle with one engine down when the aircraft is near a stall during landing. (The aircraft will be pushed to one side)

Set the altimeter to the wrong QNH, mistaking a 2 with a 3. (The aircraft can be a 1000 feet lower as expected).

Set the autopilot to an undefined high (twist the button) and then forget to set it correctly. (Making the aircraft fly too high, loosing pressure and oxygen making the aircraft fly a long way on autopilot before the engines shut down due to loss of fuel)

Fly near the Falklands during a war. (The British might use you for target practice)

Procedure flight

Startup

Fuel up the machine.

Check brakes are ON.

Check flaps are retracted.

Check spoilerons are retracted.

Check trim is centred.

Throttle on 0, the machine will auto-throttle during start-up.

Start the engines:

Manual:

Switch BATT (DC Power) to ON.

Avionics Power.

Switch to INV 1.

Right switch to ON.

Ignition switches (LH and RH) to NORM.

Click LM button on Engine Start (LH light will light up while revving up, wait till the light is off).

When you are above safety altitude reduce N1 to 85% and do as described above.

Level flight

At an altitude of 41,000 feet and with an airspeed of 220 knots (=N1 85%) you get a groundspeed of about 420 knots. This is the most economical speed and height for this aircraft. At 41,000 feet you can push it to an airspeed of near 240 knots, giving 460 KTAS, but that will hit the envelope of this aircraft.

Monitor the amount of fuel in the tiptanks. If a tiptank is below 100 Gallons open up the fuselage tank. If the fuselage tank is below 100 Gallons open up both wing tanks. The centre of gravity will move to the back of the aircraft reducing drag.

The left bearing knob (BRG O) will show the direction of NAV1 or the ADF.

The right bearing knob (BRG <> ) will show the direction of NAV2 or the ADF.

The NAV button will switch between NAV1 or NAV2 (or ILS 1 and 2) and will display the set Radial.

Avoid using FMS. Do not use NAV2 for automated flight.

Use the Autopilot Window to set the heading bug.

If a VOR has no reception it will show North. If the ADF has no reception it will show Up (tricky).

Descend

At a slant distance of about 115 NM start your descent towards the runway (assuming RW elevation of near zero AMSL, if the RW is higher you can descent later). The sink rate will be about 1970 ft/min.

Set the altitude to 10,000 AGL (so if the runway has an elevation of 1245 feet set to 11,245 feet), set speed to 170 KIAS, engines will run idle . While descending it is possible to fly very very fast at the cost of a large amount of fuel and with the risk of overspeed.

The autopilot has been tuned to give a glidepath of a bit more as 3 degrees.

At FL 180 set the altimeter to QNH. Disable Low Bank. Set the heading bug to the current course towards the runway.

Set the runway heading into the Radial of Nav 1 of the radio and set the frequency of the ILS.

At 10,000 AGL the distance to the runways should be about 30 NM. If needed use the spoilerons to slow down to increase sinkrate.

Descend to 1,500 feet AGL and aim to intercept the radial of the ILS at about 7...5 NM away from the runway. While making turns you can go to a speed of 240 KIAS. Use spoilerons to slow down.

You can only intercept the ILS radial if you are nearer as approx 40 NM of the runway. A speed below 170 KIAS can cause the aircraft to sink during high bank turns.

Cheatsheet 3 degrees altitude/distance

altitude

1

1.5

2

2.5

3

3.5

4

6

10

20

30

feet

distance

3.1

4.7

6.3

7.8

9.4

11.0

12.6

18

31

63

94

NM

( ALT(ft) * 1000 / 318.12 = Dist(NM) )

Landing

The ILS takes away the need for horizontal control. To stay inside the glidescope it is needed to change pitch (yokes) and speed (autopilot). The ILS won't work below decision height (200 feet AGL).

The intention is to slow as much as possible, but with sufficient control for a go-around.

Calculate Vref (see table above).

At a distance of 4.7 NM (attitude 1500 feet) you should intercept the glidescope on the ILS. Due to mountains or weather reception of the ILS can be hindered, the gildescope can also be caught at 1000 feet and 3.1 NM.

Flight school

Some things a pilot should be able to perform so find a nice long runway with an ILS and ask permission from ATC to do some practising. Keep the tarmac clean and don't scare the neighbours by crashing.

Restart engines

Since there is a risk that fuel runs out, forgetting to open up the fuselage or wing tanks.

Stall- landing configuration, one engine out

Landing, one engine out

Set speed to Vref +20 and don't go below that. Use pitch only to control glidescope.

Set flaps to 40o at 100...150 AGL (not earlier), immediately idle the left-over engine, land. Do not use reversers...

There should be sufficient speed and power for a controlled go-around.

After landing you can use the left-over engine to push the aircraft to the parking place.

Touch-and-go is not possible. Required RW length is double. When the speed is too low a power-up, for a go-around or to prevent a full stall, will push the aircraft uncontrollable to one side. This manoeuvre should be practised on a virtual runway well above the real one before attempting this on hard tarmac.

Go-around

This procedure (Go-around, Missed approach) should be practised and should be applied when visibility is insufficient for a landing. Practice on a virtual runway a few 100's feet above the real runway. This procedure works for normal landings and with one engine out.

At decision height (200 feet AGL, set with Primus 1000) the autopilot will shutdown and the stall warning will be disabled.

The indicated airspeed should be just above Vref or Vref + 20 with one engine out. AP should be off.

Place the file in the Models directory after making a backup of the original Paint1.png file.

Development status/Issues/Todo

Development has taken a different turn. In short, we will use the aircraft files, but we will completely redo them as like making a new aircraft. So, new interior, new exterior, new systems, new instruments etc etc.

Panel N1 and ITT now in real range with real colours (but in bars and not dials)

Different MK VIII setting

Limits and warnings on N1, spoilerons and flaps *2, reversers, engines out, stall and overspeed. Some will cause the warning sound, some will shut down the AP, some just tell the aircraft has broken up into fragments.